Nope, the font is part of the actual text contents,
but you can make keyframes for the “source text”-property and have the same text with different fonts,
then use an expression to choose the keyframe of each layer according to for instance a slider value on the master or a null layer.
Why not just multi-select the layers and change the font face for all of them at once? As long as a keyframe at a given time already exists, AE will even recognize these changes for the source text property. On the other hand it’s really a shame that AE does not offer a way to manipulate those properties via expression *sigh*